1. Field of the Invention
The present invention relates in general to a support device for a propeller shaft of motor vehicle and the propeller shaft itself. More specifically, the present invention is concerned with the support devices of a type that supports the propeller shaft to a vehicle body through an annular ball bearing.
2. Description of the Related Art
In order to clarify the present invention, the background of the propeller shaft support devices of the above-mentioned type will be briefly described in the following.
One of the support devices of such type is disclosed in Japanese Laid-open Patent Application (Tokkai) 2006-250251, particularly FIGS. 1 and 2 of the same.
That is, the disclosed support device comprises generally an annular bracket member that is fixed to a floor of a vehicle, an annular elastic member that is concentrically disposed in the annular bracket member, an annular bearing unit that is concentrically disposed in the annular elastic member and rotatably supports a propeller shaft, an annular stopper metal piece that is concentrically disposed on the propeller shaft and has an annular base part pressed against one axial end of the bearing unit to achieve positioning and fixing of the bearing unit relative to the propeller shaft, and an annular seal member that has a cylindrical outer surface secured to a cylindrical inner surface of the annular elastic member and a cylindrical inner surface slidably but sealingly put on a cylindrical outer surface of the annular base part of the annular stopper metal piece.
The annular elastic member comprises an outer annular part fixed to the annular bracket member, an inner annular part covering both the bearing unit and the seal member and a turn-up part at which the outer and inner annular parts are integrally connected.
The annular stopper metal piece comprises a smaller diameter inner part (viz., the annular base part) press-fitted on the propeller shaft, an annular flange part radially outwardly projecting from one axial end of the smaller diameter inner part and a larger diameter outer part extending from a peripheral end of the annular flange part toward the bearing unit. Thus, the stopper metal piece rotates together with the propeller shaft like a one unit.
The inner annular part of the annular elastic member is formed, at a larger diameter portion thereof facing a leading end of the larger diameter outer part of the annular stopper metal piece, with an annular recess.
A radially inner edge of the annular recess is formed into a tapered guide portion of which diameter gradually increases as a distance to the leading end of the larger diameter outer part of the annular stopper metal piece reduces.
Furthermore, the inner annular part of the annular elastic member is formed, at a smaller diameter portion thereof facing the annular flange part of the annular stopper metal piece, with an annular lip.
That is, a so-called labyrinth structure is constituted by the larger diameter outer part of the annular stopper metal piece and the larger and smaller diameter portions of the inner annular part of the annular elastic member. With this labyrinth structure, undesired penetration of water, such as rainwater, muddy water and the like, toward the smaller diameter inner part of the annular stopper metal piece is suppressed.